Re: How are Packed Fields in an RPGIII DS Represented -- RPG400-L

Packed fields (sometimes called "binary coded decimal") are stored bykeeping one decimal digit in each nibble of a byte.

Consider the decimal number 123. To make that packed, you convert eachdigit to binary, so that you have:


1 = 0001
2 = 0010
3 = 0011

Then, you need to keep track of whether your number is positive ornegative. To do that, they decided to use


positive = 1111
negative = 1101

So, to store the number 123 (as a positive number) as a packed decimal,you'd have 4 nibbles that look like this:


   0001 0010 0011 1111

Combine the nibbles to make bytes, and you have

   00010010 00111111

In hex, that would look like this:

   x'123F'

That's actually kinda nice, because it makes it easy for us to debug ournumbers. We just display them in hex and we can read the value of thenumber from them very easily.

Since data on a computer is stored in bytes, and since one nibble (half ofa byte) is always required for a sign, the number of digits in a packedfield is always: (bytes x 2) - 1

I get a syntax error in SEU That the Decimal Portion is greater than theField Length


In your case, you have the following definition

     I            DS
     I                                    P   1   36MYFLD

Since this is a field that goes from byte 1 to byte 3 of a data structure,we know that it's 3 bytes long. So how many digits is it? 3 x 2 = 6,

6 - 1  = 5.  It's 5 digits long.

In order to have 6 decimal places you need at least 6 digits. You can'ttell the computer to make 6 decimal places unless there are at least 6digits to take them from :)

But in RPG III is it  P 1    6 6
Or would this be considered a 9 position with 6 decimal

It's taking up 6 bytes. Think about that... 6 bytes is 12 nibbles. Sinceone of those nibbles is used for the sign (positive or negative) there are11 digits left.

So, this is an 11 digit number, and 6 of those digits are used as decimalplaces.

In other words, it would store a number like 99999.999999. The equivalentin DDS or ILE RPG would be "11P 6".


In the future please do us a favor and don't quote back the entire digest.